The present invention is directed to a machine for forming a full overlap shipping container. One embodiment of the machine forms an intermediate product by laminating single side panels of the two blanks. A second embodiment is useful for preparing a fully assembled container ready for erection and filling.
Full overlap shipping containers are those in which at least two of the side walls have double thicknesses of corrugated board. A container of this type is shown in U.S. Pat. No. 3,543,994 to Clark. Full overlap containers have superior stacking strength without the necessity for making complex and expensive interior inserts.
Full overlap containers have been found advantageous for shipping many products of commerce. Shelled nuts are one example. One application requires a container that can hold 50 lbs. of shelled almonds and be stacked five high on a pallet and five pallets high. In essence, this means that the lower-most container must support a load of almost 1,300 lbs. without crushing. A standard full overlap container requires a special insert for this application.
It is has been impractical to make a full overlap container with four sides having a double thickness from a single blank. Normally, two essentially identical blanks are used with the side panels being laminated. Unfortunately, these containers have not had wide usage because of the high expense involved in assembling them. Prior to the present invention, no machinery was in existence for gluing the two blanks together in an appropriate fashion and it was necessary to do this operation by hand. The present invention has overcome this problem. It can optionally prepare a flat blank, in which only one set of side panels are glued, or it can prepare a fully assembled container in which both sets of side panels are glued. In the former case, assembly can be completed on existing equipment such as a printer-slotter or a folder-gluer.